Kinetic Study of the Hydrogen Oxidation Reaction on Nanostructured Iridium Electrodes in Acid Solutions

The hydrogen oxidation reaction was studied on a rotating disc electrode of nanostructured iridium supported on glassy carbon. The electrode was prepared via sputtering and further annealing at 400 °C under a hydrogen atmosphere to avoid the presence of iridium oxide. The iridium film was analyzed b...

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Bibliographic Details
Published in:	Journal of physical chemistry. C 2013-12, Vol.117 (48), p.25269-25275
Main Authors:	Montero, M. Angeles, Fernández, José L, Gennero de Chialvo, M. Rosa, Chialvo, Abel C
Format:	Article
Language:	eng
Subjects:	Annealing Applied sciences Condensed matter: structure, mechanical and thermal properties Corrosion Corrosion mechanisms Cross-disciplinary physics: materials science rheology Deposition by sputtering Exact sciences and technology Heat treatment Materials science Metals. Metallurgy Methods of deposition of films and coatings film growth and epitaxy Physics Production techniques Solid surfaces and solid-solid interfaces Surfaces and interfaces thin films and whiskers (structure and nonelectronic properties)
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Summary:	The hydrogen oxidation reaction was studied on a rotating disc electrode of nanostructured iridium supported on glassy carbon. The electrode was prepared via sputtering and further annealing at 400 °C under a hydrogen atmosphere to avoid the presence of iridium oxide. The iridium film was analyzed by microscopic (scanning electron microscopy (SEM), atomic force microscopy (AFM)), spectroscopic (X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS)), and electrochemical (cyclic voltammetry) techniques, which allowed us to verify the nanostructured morphology and the absence of any phase other than metallic iridium. The real surface area was evaluated by adsorption of underpotential deposition (UDP) hydrogen and CO stripping. Experimental current–overpotential (η) curves of the hydrogen oxidation reaction were obtained in the range −0.03 V ≤ η ≤ 0.20 V at different rotation rates in sulfuric acid solution. They were correlated by kinetic expressions, and the corresponding values of the kinetic parameters were evaluated. It was verified that over this overpotential region the reaction proceeds almost purely through the Tafel–Volmer route. Moreover, an exchange current density j o = 1.34 mA cm–2 was calculated.
ISSN:	1932-7447 1932-7455